Electrical equipment



Dec. 26,' 1933. c. w. wYMAN 1,940,927

ELECTRICAL EQUIPMENT Filed Aug. 1e, 1930 I a l u l l l Patented Dec. 26,1933 PATIENT OFFICE ELECTRICAL EQUIPMENT Charles W. Wyman, Claremont, N.H., assigner to Sullivan Machinery Company, a corporation ofMassachusetts Application August 16, 1930. Serial No. 475,685

11 Claims.

This invention relates to improved electrical control equipment andcircuits, especially adapted for coal mining machines or other coalmining equipment wherein a high degree of safety is desired in additionto ease and positiveness of operation.

In the operation of coal mining equipment of the electrically driventype, it is usual to run cables from the main line located in the entrytoV the mining equipment such as coal mining machines or trucks whichmay be disposed or traveling at a considerable distance from the mainline; In my improved arrangement it is desired to eflect certainautomatic operations ysuch as are discloeed in my co-pendingapplication, Serial No. 329,928, filed Jan. 2, 1929 (now Patent No.1,844,910), and to have the principal controls and circuits disposednear the main line with a suitable pilot circuit mounted on the miningequipment for placing the main control circuits in operation or cuttingthem out. It'is further desirable to have the arrangement such that whenthe mining equipment is being transportedl the operator may. in theusual manner simply place the trolley against one of the main linescomprising the trolley wire and when it is desired to stop, to pull thetrolley off. Thus the operatonmay make intermittent contacts of thetrolley with the trolley wire to control the rate of transportation or.the distance he may wish tov travel. It is also desirable to eliminatethev necessity for any attention onV the part of the operator otherthaneither to close the pilot circuit or operate the trolley, and yet insurethe utmost safety in the way of not allowing the motor to have fullcurrent thrown thereon when the trolley is touched to the Wire while atthe same time insuring that the motor will be promptly brought up tofull speed when the circuits are initially closed. Other desiredfeatures include safety controls such as overload and low voltagecontrols.

It is an object of my invention to accomplish the above and otherfunctions in an improved manner over that disclosed in my abovementioned co-pending application and any applications that might beincorporated therein, and also to provide improved means for breakingboth lines of the motor circuit thus necessitating in actual practicethe use of a double main line contacter. l

Other objects and advantages will be more apparent to those skilled inthe art and other modifications and arrangements will likewise beapparent to such persons from the following description of theaccompanying drawing in which,

Fig. 1 is a wiring diagram showing diagrami matically the circuits andcontrols; and Y Fig. 2 isa diagrammatic view of one portion of apreferred form of switch which is mounted upon the mining machine.

In the illustrative embodiment of the invention the electrical portionsof a mining machine proper `are diagrammatically illustrated at A.

B represents a multi-wire flexible cable which 35 serves to connect themining machine with a controlling mechanism generally designated C,which is preferably arranged in a box or the like upon a truck. Themining machine A may be of a type which works when supported directlyupon the mine bottom and at a distance from the truck or' it may form anintegral part of a mounted mining machine which performs its cuttingoperations while supported upon the wheels of the truck. Insucha casethe cable B will not be of great length, though when the controllingsystem is used for a machine of the dismountable type, the machine A maybe at a substantial distance from the control apparatus C at times, sothat the cable B may necessarily be of substantial length. Duringtransport, however, the machine A may be mounted directly upon the truckand therefore in close adjacency to the control apparatus C.Irrespective of which type of mining apparatus is employed, current maybe supplied to the apparatus as a whole from a trolley wire T anda trackrail R, and during vcontrol of the apparatus during transport from placeto place control may be conveniently effect? ed by intermittently makingcontact with the trolley wire T through a trolley clip 3, it beingunderstood that the power for effecting transport will preferably bederived from the motor forming a part of the lmining machine.

It is to be understood that this improved control system is in no sense,however, limited to use with mining apparatus, though it finds a veryadvantageous field for employment with such mechanisms.

Referring more particularly to the drawing, two main control leads 1 and2 are shown as con. nected respectively to the sides of the main line T.R, as. by a trolley clip or contact 3 and any other contact device Dwhose form depends on the circumstances. While main control leads havebeen shown for simplification, it is, of course, understood that thewiring may and most likely will assume a form of lay-out such as will besuitable for the machine with which it is associated or the operatingelements therefor. In

the operation, the operator flrst closes main control switch 4 whereuponcurrent ows from control lead 1 through solenoid 5 and pilot wire 6 onthrough the machine pilot control associated with the mining machine andgenerally indicated at 7, and thence back to the main line as by pilotwire 8. Completion of this circuit is of course dependent upon theoperator closing a pilot switch 67 in the control of the mining machineA. Energization of solenoid 5 closes switch 9 thereby energizing lowvoltage coil 10 by current flowing through wires 11 and 12 back to theother control lead 2, thus closing switch 13 and opening a switch 14,later described. Simultaneously with supply of current to solenoid 10,current ows through a circuit including a conductor 15, a coil 19, whoseconstruction and characteristics will later be described, and a pair ofnormally closed switches 17 and 16. The coil 19 controls a pair ofswitches 20 and 21, of which the former is opened and the latter closedwhen the coil 19 is supplied with current. Closure of switch 21, sinceswitch 13 is already closed, permits current to ow through conductor 1,switches 4, 9, 13 and 21, a normally closed switch 25, wire 26, asolenoid 27 and a further conductor 28, to the conductor2. Energizedsolenoid 27 closes a contactor 34'r1 disposed in one of the motor leads34 which is connected to the lead l. It also closes a switch 29a and aswitch 23, whose functions will later appear. Simultaneously withenergizing of solenoid 27, current ilow's through conductor 1, switches4, 9, 13, 21 and 25 throughv a solenoid 29 and a normally closed switch31 to the lead 2, thereby causing solenoid 29 to close the motorcontactor 32 and at the same time to open the switch 17 previouslymentioned. It may here be noted that both leads to the motor arepractically simultanecuslyclosed, one by contactor 34, and the other bycontactor 32, and thus a circuit including the full resistance 40, 41 inseries with the motor is established, this circuit including conductors1 and 34, a solenoid 35, contacter 34, overload relay coil 36, conductor37, the motor windings, conductor 39, the resistances 40, 41, contactor32, and lead 2. Solenoid 35 closes a switch 24, which, with the switch23 closed, establishes a current path in parallel with that controlledby the switches 13 and 21.

Upon closure of switch 32 it will be noted that current ilows through acoil 47, in parallel with resistance 40, thereby opening a switch 48,later mentioned in more detail. Closure of switch 32 is accompanied byopening of switch 17, as previously noted, thereby causing deenergizingof solenoid 19 and closing of switch 20 and opening of switch 21.However, the action of solenoid 19 upon being deenergized, with theconsequent opening of switch 2l, is sufficiently delayed so that seriesrelay 35 has closed switch 24 before switch 21 opens, so that the maincontrol circuit through the solenoid 29 is maintained by current owingthrough the main control lead 1, switches 4, 9, 24 and 23, switch 25,coil 29, switch 31. and back to the control' lead 2. The elementdescribed as solenoid 19 may advantageously take the form of a copperjacketed core, electromag-` net, so constructed that on breaking of thecircuit through the winding the magneto motive force will be maintainedfor a definite interval before the parts controlled thereby will move.

To cut out the motor circuit resistance in steps and thereby suitablyincrease current flow to the motor, upon deenergization of solenoid 19and consequent closure oi' switch 20. a solenoid 43 is energized as bycurrent flowing from the conductor 1 through switches 4, 9, 24, 23,v 25,20, Wires 44, 45, and switch 31 to the other control lead 2.Energization of solenoid 43 closes switch 46 thereby shunting resistance40 and permitting increased current flow to the motor. It will be notedthat upon closure of switch 46 solenoid 47, which was energized whencurrent initially flowed through wire 39, is deenergized, beingshort-circuited, to permit the closure of its switch 48, whereuponcurrent flows between the control leads l and 2 as by way of switches 4,9, 24, 23, 25 and 20, wires 44 and 49, switch 48, a solenoid 50, andback to the control lead 2, whereupon energization of the solenoid 50causes closure of a switch 51, thereby entirely cutting out resistances40 and 41. Closure of switch 51, however, is accompanied by opening ofswitches 31 and 16, whereby even though solenoid 29 deenergizes, andpermits reclosureof switch 17, still solenoid 19 will not bereenergizedto open switch 20 so as to disturb the energization ofsolenoid 50, because switch 16 by being open prevents reenergization cfsolenoid 19. The making of the element designated solenoid 47 of arelatively high self-inductance insures a suitable delay between theclosure of switches 46 and 51.

Upon occurrence of a predetermined overload current, solenoid 36 will besufficiently energized to close the overload switch 53, therebyenergizing solenoid 54 by current flowing through a wire 55, switch 53,solenoid 54, a wire 56 and thence to control lead 2. Energization ofsolenoid 54 closes a holding circuit switch 57 and opens switch 25,thereby causing opening of main motor switch 5l, and maintaining of thesame open due to solenoid 54 being maintained energized by current owingfrom wires 1l and l5 through switch 57 and solenoid 54 to wires 56 and2, the latter being not affected by opening of switch 25. Thus the motorcircuit cannot be automatically reestablished until the overloadcondition is eliminated. To attempt automatic reestablishment of themotor circuit it is first necessary to break the holding circuit forsolenoid 54 and this involves opening of the pilot switch on the machineA to deenergize solenoid 5 and open switch 9, or the panel switch 4 maybe opened likewise to deenergize solenoid 5. In either case, opening ofswitch 9 breaks the holding circuit through wires 1l and 15 and switch57, to thus deenergize solenoid 54 and permit reclosure of switch 25.Hence upon manually reclosing either panel switch 4 or the pilot switch67, solenoid 5 will be reenergized and the sequence of startingoperations automatically initiated. However, if the overload conditionsstill prevail the overload coil 36 will be reenergized when the motorcurrent reaches the predetermined amount, thus again effecting openingof switch 25 and breaking the motor circuit. The operator can of courseintermittently break or close the pilot switch 67 of the panel switch 4until the overload condition is eliminated, it being noted thatthroughout any of these operations the machine or equipment is notendangered, for the various switches and resistances 40 and 41 areautomatically controlled and each time the motor circuit is broken bothpower connections are broken as by switches 34a and 51. This addsconsiderably to the safety of operation. When the overload condition isnally corrected, the equipment will continue to function and the motorstarting resistance will finally be automatically cut out entirely, thusrequiring not only a minimum amount of attention on the part of theoperator as far as .the electrical controls are concerned, but alsoproviding v51 is thereby opened in the same manner as previouslydescribed for the overload condition.A

Before the motor circuit can be reestablished normal voltage must berestored, whereupon low voltage vsolenoid l0 is reenergized to openswitch 14 and close switch 13, thereby permitting the sequence ofstarting operations.

Due to breaking both lines 34 and 39 of the motor circuit, it isnecessary to provide a return pilot wire 8 and connect the same to thewire 2 on the rline side of switch 51 so vas to permit current to besupplied to the solenoid 5 when the pilot switch on the mining machine Ais closed. Inasmuch as the controller, mounted on lthe mining machine,and its circuits yhave been described in detail in Patent No. 1,844,910,it is not necessary to describe the same again, It may be said, however,as tol Fig. l which diagrammatically shows rtwo pilot contacts 67, thatthe two Acon-- tacts may be connected by a conductor and by the latterto return pilot wire 8; while as actually used in a preferredconstruction, a pivoted type pilot switch element is movable Ato connectconductor 6 with return pilot wire 8 kupon engagement with a stationarycontact 67a.

Another important improvement presented by my improved controllingmechanism resides in the fact that a system particularly,useful introlleying abouta mine is provided. It will be noted that by. breakingthe circuit, as by removing the trolley clip 3 from contact with thetrolley wire, the entire motor control lsystem will immediately bereturned to off condition and upon reapplication of the trolley clip tothe trolley wire, the entire sequence of operations including theinitial making of a circuit through all the resistance and the step bystep cutting out of the resistance will automatically take place. therebeing no possibility'of injuring the motor by the passing of full linecurrent directly throughthe motor lwindings when the latter isstationary or barely turning over because by reason of the relationshipof the various ycontrol elements, initial establishment of any circuitthrough the motor necessarily includes all the resistance.

From the foregoing it is seen that'I have provided an improved control,having all of the desired characteristics which are conducive to safetyand leffectiveness of operation, including for instance the breaking ofeach motor line as by switches 34BL and 51 without interfering withope-ration of the pilot circuit, thus permitting the operator to remainat the machine and eiect any vdesired control over the various circuits.

While there is in this application specifically described one form whichthe invention may asy sume in practice, it will be understood that thisform of the same is shown for purposes of illustration and that theinvention may be modied and embodied in various other forms withoutdeparting from its spirit or the scope of the appended claims.

What I claim las new and desire to secure by Letters Patent is:

1. In combination, an electric `motor having a plurality of `terminalleads, a starting resistance, and means for connecting said motor leadsto the opposite sides of a power line including switch devices forsimultaneously connecting one of said leads with one side of said powerline and the other of said leads through said starting resistance withthe other of said power lines, and means for automatically thereaftercutting out said resistance and connecting said second lead directly tosaid second mentioned side of said power line including controllingdevices one of which is associated with and moves with each of saidswitch devices.

2. v1in combination, an electric motor having a plurality of leads, astarting resistance, and means for connecting said motor leads to theopposite sides of a power line including switch devices forsimultaneously connecting one of said leads with one side of said powerline and the other of said leads through said starting resistance withthe other of said power lines, and electro-magnetic means forauomatically'thereafter cutting out said resistance in a plurality ofsteps and connecting said second lead directly to said second mentionedside of said power line, said electromagnetic means having a controllingcircuit containing switchesv one of which is governed by movement of oneof said switch devices and another of which is governed by .movement ofanother of said switch devices.

3. .In an electric motor control-system, a motor having terminal powerleads, main power lines, a resistance, aplurality of switches, includingswitches for respectively connecting the different leads of said motorwith the power lines, arranged first to connect the motor to the linesthrough the resistance and then in suitably timed relation to cut outvthe resistance,'electro-magnetic means arranged to be energized toeffect closing of each of said switches, control circuits for supplyingcurrent to said electro-magnetic means to effect operation of saidswitches in predetermined order including switches one moved by each ofthe electro-magnetic operating means for the switches which respectivelyconnect the different motor leads with the power lines, and an operatorcontrollable switch governing said control circuits.

4. In an `electric motor control system, a motor having terminal powerleads, main power lines, a starting resistance, a plurality of switchesin-g cluding 4a switch for connecting one motor lead through theresistance to one power line, a switch for connecting the same motorlead to the same power line independently of said resistance, and aswitch for connecting another motor lead to another power lineindependently of the resistance, electro-magnetic means for operatingsaid switches, control circuits for supplying current to saidelectro-magnetic means to effect a closing of said rst and thirdswitches together and subsequent closure of said second switch includingswitches -moved by the electro-magnetic operating means of each of saidthree switches, and an operator controlled switch governing said controlcircuits.

5. In an electric motor control system, a motor vhaving power leads,main power lines, a startsaid resistance and for connecting anothermotor lead to another power line independently of said resistance,electro-magnetic means for operating each of said switches, a controlcircuit for supplying current to said electro-magnetic means to eiectopera-r tion of said switches in predetermined sequence, and means forautomatically breaking the circuit through the electro-magnetic meansfor operating the switch for connecting the motor lead throughtheresistance to a power line, on closing of the second mentioned switch,and an ,operator controllable switch in said control circuit.

6. In an electric motor control system, a motor having power leads, mainpower lines, a starting resistance, a switch for connecting one of saidmotor leads to a power line independently of the resistance, switchesfor connecting another motor lead to a different power line through saidresistance and for progressively cutting out said resistance in apredetermined manner including a switch for connecting the lastmentioned power lead to the last mentioned power line independently ofthe resistance, electromagnetic means for operating each of saidswitches, a control circuit for supplying current to saidelectro-magnetic means to effect operation of said switches inpredetermined sequence, and mechanical means for automatically breakingthe circuit through all of said electro-magnetic means except the onesfor operating the last switch and the first mentioned switch on theclosine of the last switch, and an operator controllable switch in saidcontrol circuit.

7. In combination, an electric motor having power leads, power linesconstituting the sole source of current supplied tothe motor windings,and automatic controlling apparatus for said motor including a startingresistance, electromagnetically actuated contactor devices forsimultaneously connecting each of the motor leads with the lines, withthe starting resistance in series with the motor, and thereafterautomatically' cutting out the resistance, controlling means for saidcontactor devices including a pilot circuit and automatically controlledcircuits for effecting serial operation of saidcontactor devices,certain of said automatically controlled circuits including a relayresponsive to low voltage and automatically operative to eiectreinsertion of the resistance in the motor circuit, but inoperative tomaintain the motor disconnected from the line, on a substantial drop inline voltage.

8. In combination, an electric motor having a plurality of power leads,a resistance, a power line. automatic controlling apparatus forconnecting said motor to the line initially through the resistance andoperative gradually to cut out place the motor directly on the line,said automatic controlling apparatus including contactors controllingeach of the motor leads, and having a common pilot control circuit, andmeans operative upon a predetermined reduction in line voltage forautomatically resetting said controlling apparatus so as to connect themotor to the power line through the resistance,

and on return of the normal power supply, gradually to'cut out saidresistance and place the motor directly on the line after apredetermined time interval.-

9. In combination, a source ofv power, amotor, said motor having aplurality of power leads, a resistance, primary circuit making andresistance short-circuiting contactors operating in sequence forconnecting the motor to a source of power through said resistance andgradually cutting out said resistance, said primary circuit includingcontactors controlling each of the motor out the resistance on return ofthe normal power supply. v

10. In combination, an electric motor having leads, a power lineconstituting the sole source of current supply to the motor windings,automatic voltage drop in the power supply to interrupt the controlcircuit for the nal contactor and on recurrence of normal voltage toestablish a circuit through the initial contactor to permit starting ofthe motor through said resistance.

11. In combination, a motor, a reverse switch, conductors associatedtherewith including a pair of leads constituting one of said firstelectro-magnetic operating means closure of said rst mentionedcontactors substantially simultaneously, subsequent closure of saidcontactor for shunting part of said resistance, and nally closure ofsaid second mentioned resistance short-circuiting contactor, saidcircuits CHARLES W. WYMAN.

